Field of the Invention
The present invention relates to a heavy duty pneumatic tire that may exhibit an excellent chipping resistance and low rolling resistance.
Description of the Related Art
Japanese Unexamined Patent Application Publication No. 2006-315579 discloses a heavy duty pneumatic tire including a tread portion provided with a plurality of tread blocks that are separated by circumferentially extending main grooves and a plurality of lateral grooves. Typically, the heavy duty pneumatic tire having a lot of lateral grooves has low circumferential pattern rigidity. Unfortunately, such a heavy duty pneumatic tire tends to have high rolling resistance due to a large energy loss generated by deformation of the tread blocks when coming into contact with the road.
In order to improve the rolling resistance of the tire, a tire having a tread portion with less lateral grooves to enhance the circumferential rigidity has been proposed. Unfortunately, such a heavy duty pneumatic tire tends to have low chipping resistance where a small piece of tread rubber is easily chipped from a tread block subjected to a large ground contact pressure.